
The amount of energy released when ${{10}^{0}}$atoms of iodine in vapor state are converted to ${{I}^{-}}$ions is $4.9\times {{10}^{-13}}J$. What is the electron affinity of iodine in eV per atom?
(A)- 2.0
(B)- 2.5
(C)- 2.75
(D)- 3.0
Answer
474k+ views
Hint: The amount of energy released when an electron is added to a neutral atom to form an anion is known as the electron affinity.
Complete Step by step answer:
-In other words, the potential energy change of the atom when an electron is added to a neutral atom in its gaseous state forming a negative ion is known as the electron affinity of the particular atom.
-In respect to the question, electron affinity can be described as the amount of energy released when one mole of iodine or $6.022\times {{10}^{23}}$ atoms of iodine in their gaseous state are converted into ${{I}^{-}}$ion. Let us now write the chemical equation for the question-
$I+{{e}^{-}}\to {{I}^{-}}$
-According to the question, electron affinity (E.A)$=4.9\times {{10}^{-18}}J$
Therefore, the amount of energy released when $6.022\times {{10}^{23}}$atoms of iodine in their gaseous state are converted into ${{I}^{-}}$ions $=\dfrac{4.9\times {{10}^{-13}}}{{{10}^{6}}}\times 6.022\times {{10}^{23}}=29.5\times {{10}^{4}}Jmo{{l}^{-1}}=295KJmo{{l}^{-1}}$
-Since $96.3KJmo{{l}^{-1}}=1eV\text{ ato}{{\text{m}}^{-1}}$
Therefore, $295KJmo{{l}^{-1}}=\dfrac{1\times 295}{96.3}eV\text{ ato}{{\text{m}}^{-1}}=3.06eV\text{ ato}{{\text{m}}^{-1}}$
So, the correct answer is option D.
Note: -The electron affinity has a general trend along the groups and periods in the periodic table. Electron affinity on going from left to right across a period increases as the nuclear attraction increases. Electron affinity on going down in the group decreases as the electrons are less tightly bonded and therefore closer in energy to a free electron.
-Electron affinity depends on the following factors-
(i) Atomic size- Smaller the size of the atom, the greater will the electron gain enthalpy because greater will be the nuclear forces.
(ii) Nuclear charge- Greater the nuclear charger, the larger the value for electron gain enthalpy as an increase in nuclear charge will increase the effective nuclear force on valence electrons.
(iii) Screening effect- Electron affinity is inversely proportional to the screening effect, that is larger the screening effect lesser the electron gain enthalpy because lesser will be the nuclear force.
-In general electron affinity follows the following trend-
\[\text{Halogens Oxygen family Carbon family Nitrogen family Metals of group 1 and 13 Metals of group 2}\]
Complete Step by step answer:
-In other words, the potential energy change of the atom when an electron is added to a neutral atom in its gaseous state forming a negative ion is known as the electron affinity of the particular atom.
-In respect to the question, electron affinity can be described as the amount of energy released when one mole of iodine or $6.022\times {{10}^{23}}$ atoms of iodine in their gaseous state are converted into ${{I}^{-}}$ion. Let us now write the chemical equation for the question-
$I+{{e}^{-}}\to {{I}^{-}}$
-According to the question, electron affinity (E.A)$=4.9\times {{10}^{-18}}J$
Therefore, the amount of energy released when $6.022\times {{10}^{23}}$atoms of iodine in their gaseous state are converted into ${{I}^{-}}$ions $=\dfrac{4.9\times {{10}^{-13}}}{{{10}^{6}}}\times 6.022\times {{10}^{23}}=29.5\times {{10}^{4}}Jmo{{l}^{-1}}=295KJmo{{l}^{-1}}$
-Since $96.3KJmo{{l}^{-1}}=1eV\text{ ato}{{\text{m}}^{-1}}$
Therefore, $295KJmo{{l}^{-1}}=\dfrac{1\times 295}{96.3}eV\text{ ato}{{\text{m}}^{-1}}=3.06eV\text{ ato}{{\text{m}}^{-1}}$
So, the correct answer is option D.
Note: -The electron affinity has a general trend along the groups and periods in the periodic table. Electron affinity on going from left to right across a period increases as the nuclear attraction increases. Electron affinity on going down in the group decreases as the electrons are less tightly bonded and therefore closer in energy to a free electron.
-Electron affinity depends on the following factors-
(i) Atomic size- Smaller the size of the atom, the greater will the electron gain enthalpy because greater will be the nuclear forces.
(ii) Nuclear charge- Greater the nuclear charger, the larger the value for electron gain enthalpy as an increase in nuclear charge will increase the effective nuclear force on valence electrons.
(iii) Screening effect- Electron affinity is inversely proportional to the screening effect, that is larger the screening effect lesser the electron gain enthalpy because lesser will be the nuclear force.
-In general electron affinity follows the following trend-
\[\text{Halogens Oxygen family Carbon family Nitrogen family Metals of group 1 and 13 Metals of group 2}\]
Recently Updated Pages
Master Class 11 Accountancy: Engaging Questions & Answers for Success

Glucose when reduced with HI and red Phosphorus gives class 11 chemistry CBSE

The highest possible oxidation states of Uranium and class 11 chemistry CBSE

Find the value of x if the mode of the following data class 11 maths CBSE

Which of the following can be used in the Friedel Crafts class 11 chemistry CBSE

A sphere of mass 40 kg is attracted by a second sphere class 11 physics CBSE

Trending doubts
10 examples of friction in our daily life

One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Difference Between Prokaryotic Cells and Eukaryotic Cells

State and prove Bernoullis theorem class 11 physics CBSE

What organs are located on the left side of your body class 11 biology CBSE

The combining capacity of an element is known as i class 11 chemistry CBSE
